1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
16 use core::borrow::BorrowFrom;
17 use core::cmp::Ordering::{self, Less, Greater, Equal};
18 use core::default::Default;
22 use core::iter::{Peekable, Map, FromIterator};
23 use core::ops::{BitOr, BitAnd, BitXor, Sub};
25 use btree_map::{BTreeMap, Keys};
27 // FIXME(conventions): implement bounded iterators
29 /// A set based on a B-Tree.
31 /// See BTreeMap's documentation for a detailed discussion of this collection's performance
32 /// benefits and drawbacks.
33 #[derive(Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
35 pub struct BTreeSet<T>{
39 /// An iterator over a BTreeSet's items.
41 pub struct Iter<'a, T: 'a> {
45 /// An owning iterator over a BTreeSet's items.
47 pub struct IntoIter<T> {
48 iter: Map<(T, ()), T, ::btree_map::IntoIter<T, ()>, fn((T, ())) -> T>
51 /// A lazy iterator producing elements in the set difference (in-order).
53 pub struct Difference<'a, T:'a> {
54 a: Peekable<&'a T, Iter<'a, T>>,
55 b: Peekable<&'a T, Iter<'a, T>>,
58 /// A lazy iterator producing elements in the set symmetric difference (in-order).
60 pub struct SymmetricDifference<'a, T:'a> {
61 a: Peekable<&'a T, Iter<'a, T>>,
62 b: Peekable<&'a T, Iter<'a, T>>,
65 /// A lazy iterator producing elements in the set intersection (in-order).
67 pub struct Intersection<'a, T:'a> {
68 a: Peekable<&'a T, Iter<'a, T>>,
69 b: Peekable<&'a T, Iter<'a, T>>,
72 /// A lazy iterator producing elements in the set union (in-order).
74 pub struct Union<'a, T:'a> {
75 a: Peekable<&'a T, Iter<'a, T>>,
76 b: Peekable<&'a T, Iter<'a, T>>,
79 impl<T: Ord> BTreeSet<T> {
80 /// Makes a new BTreeSet with a reasonable choice of B.
85 /// use std::collections::BTreeSet;
87 /// let mut set: BTreeSet<int> = BTreeSet::new();
90 pub fn new() -> BTreeSet<T> {
91 BTreeSet { map: BTreeMap::new() }
94 /// Makes a new BTreeSet with the given B.
96 /// B cannot be less than 2.
97 #[unstable = "probably want this to be on the type, eventually"]
98 pub fn with_b(b: uint) -> BTreeSet<T> {
99 BTreeSet { map: BTreeMap::with_b(b) }
103 impl<T> BTreeSet<T> {
104 /// Gets an iterator over the BTreeSet's contents.
109 /// use std::collections::BTreeSet;
111 /// let set: BTreeSet<uint> = [1u, 2, 3, 4].iter().map(|&x| x).collect();
113 /// for x in set.iter() {
114 /// println!("{}", x);
117 /// let v: Vec<uint> = set.iter().map(|&x| x).collect();
118 /// assert_eq!(v, vec![1u,2,3,4]);
121 pub fn iter(&self) -> Iter<T> {
122 Iter { iter: self.map.keys() }
125 /// Gets an iterator for moving out the BtreeSet's contents.
130 /// use std::collections::BTreeSet;
132 /// let set: BTreeSet<uint> = [1u, 2, 3, 4].iter().map(|&x| x).collect();
134 /// let v: Vec<uint> = set.into_iter().collect();
135 /// assert_eq!(v, vec![1u,2,3,4]);
138 pub fn into_iter(self) -> IntoIter<T> {
139 fn first<A, B>((a, _): (A, B)) -> A { a }
140 let first: fn((T, ())) -> T = first; // coerce to fn pointer
142 IntoIter { iter: self.map.into_iter().map(first) }
146 impl<T: Ord> BTreeSet<T> {
147 /// Visits the values representing the difference, in ascending order.
152 /// use std::collections::BTreeSet;
154 /// let mut a = BTreeSet::new();
158 /// let mut b = BTreeSet::new();
162 /// let diff: Vec<uint> = a.difference(&b).cloned().collect();
163 /// assert_eq!(diff, vec![1u]);
166 pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> {
167 Difference{a: self.iter().peekable(), b: other.iter().peekable()}
170 /// Visits the values representing the symmetric difference, in ascending order.
175 /// use std::collections::BTreeSet;
177 /// let mut a = BTreeSet::new();
181 /// let mut b = BTreeSet::new();
185 /// let sym_diff: Vec<uint> = a.symmetric_difference(&b).cloned().collect();
186 /// assert_eq!(sym_diff, vec![1u,3]);
189 pub fn symmetric_difference<'a>(&'a self, other: &'a BTreeSet<T>)
190 -> SymmetricDifference<'a, T> {
191 SymmetricDifference{a: self.iter().peekable(), b: other.iter().peekable()}
194 /// Visits the values representing the intersection, in ascending order.
199 /// use std::collections::BTreeSet;
201 /// let mut a = BTreeSet::new();
205 /// let mut b = BTreeSet::new();
209 /// let intersection: Vec<uint> = a.intersection(&b).cloned().collect();
210 /// assert_eq!(intersection, vec![2u]);
213 pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>)
214 -> Intersection<'a, T> {
215 Intersection{a: self.iter().peekable(), b: other.iter().peekable()}
218 /// Visits the values representing the union, in ascending order.
223 /// use std::collections::BTreeSet;
225 /// let mut a = BTreeSet::new();
228 /// let mut b = BTreeSet::new();
231 /// let union: Vec<uint> = a.union(&b).cloned().collect();
232 /// assert_eq!(union, vec![1u,2]);
235 pub fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> Union<'a, T> {
236 Union{a: self.iter().peekable(), b: other.iter().peekable()}
239 /// Return the number of elements in the set
244 /// use std::collections::BTreeSet;
246 /// let mut v = BTreeSet::new();
247 /// assert_eq!(v.len(), 0);
249 /// assert_eq!(v.len(), 1);
252 pub fn len(&self) -> uint { self.map.len() }
254 /// Returns true if the set contains no elements
259 /// use std::collections::BTreeSet;
261 /// let mut v = BTreeSet::new();
262 /// assert!(v.is_empty());
264 /// assert!(!v.is_empty());
267 pub fn is_empty(&self) -> bool { self.len() == 0 }
269 /// Clears the set, removing all values.
274 /// use std::collections::BTreeSet;
276 /// let mut v = BTreeSet::new();
279 /// assert!(v.is_empty());
282 pub fn clear(&mut self) {
286 /// Returns `true` if the set contains a value.
288 /// The value may be any borrowed form of the set's value type,
289 /// but the ordering on the borrowed form *must* match the
290 /// ordering on the value type.
295 /// use std::collections::BTreeSet;
297 /// let set: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
298 /// assert_eq!(set.contains(&1), true);
299 /// assert_eq!(set.contains(&4), false);
302 pub fn contains<Sized? Q>(&self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
303 self.map.contains_key(value)
306 /// Returns `true` if the set has no elements in common with `other`.
307 /// This is equivalent to checking for an empty intersection.
312 /// use std::collections::BTreeSet;
314 /// let a: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
315 /// let mut b: BTreeSet<int> = BTreeSet::new();
317 /// assert_eq!(a.is_disjoint(&b), true);
319 /// assert_eq!(a.is_disjoint(&b), true);
321 /// assert_eq!(a.is_disjoint(&b), false);
324 pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool {
325 self.intersection(other).next().is_none()
328 /// Returns `true` if the set is a subset of another.
333 /// use std::collections::BTreeSet;
335 /// let sup: BTreeSet<int> = [1i, 2, 3].iter().map(|&x| x).collect();
336 /// let mut set: BTreeSet<int> = BTreeSet::new();
338 /// assert_eq!(set.is_subset(&sup), true);
340 /// assert_eq!(set.is_subset(&sup), true);
342 /// assert_eq!(set.is_subset(&sup), false);
345 pub fn is_subset(&self, other: &BTreeSet<T>) -> bool {
346 // Stolen from TreeMap
347 let mut x = self.iter();
348 let mut y = other.iter();
349 let mut a = x.next();
350 let mut b = y.next();
361 Greater => return false,
362 Equal => a = x.next(),
370 /// Returns `true` if the set is a superset of another.
375 /// use std::collections::BTreeSet;
377 /// let sub: BTreeSet<int> = [1i, 2].iter().map(|&x| x).collect();
378 /// let mut set: BTreeSet<int> = BTreeSet::new();
380 /// assert_eq!(set.is_superset(&sub), false);
384 /// assert_eq!(set.is_superset(&sub), false);
387 /// assert_eq!(set.is_superset(&sub), true);
390 pub fn is_superset(&self, other: &BTreeSet<T>) -> bool {
391 other.is_subset(self)
394 /// Adds a value to the set. Returns `true` if the value was not already
395 /// present in the set.
400 /// use std::collections::BTreeSet;
402 /// let mut set = BTreeSet::new();
404 /// assert_eq!(set.insert(2i), true);
405 /// assert_eq!(set.insert(2i), false);
406 /// assert_eq!(set.len(), 1);
409 pub fn insert(&mut self, value: T) -> bool {
410 self.map.insert(value, ()).is_none()
413 /// Removes a value from the set. Returns `true` if the value was
414 /// present in the set.
416 /// The value may be any borrowed form of the set's value type,
417 /// but the ordering on the borrowed form *must* match the
418 /// ordering on the value type.
423 /// use std::collections::BTreeSet;
425 /// let mut set = BTreeSet::new();
428 /// assert_eq!(set.remove(&2), true);
429 /// assert_eq!(set.remove(&2), false);
432 pub fn remove<Sized? Q>(&mut self, value: &Q) -> bool where Q: BorrowFrom<T> + Ord {
433 self.map.remove(value).is_some()
438 impl<T: Ord> FromIterator<T> for BTreeSet<T> {
439 fn from_iter<Iter: Iterator<Item=T>>(iter: Iter) -> BTreeSet<T> {
440 let mut set = BTreeSet::new();
447 impl<T: Ord> Extend<T> for BTreeSet<T> {
449 fn extend<Iter: Iterator<Item=T>>(&mut self, mut iter: Iter) {
457 impl<T: Ord> Default for BTreeSet<T> {
459 fn default() -> BTreeSet<T> {
465 impl<'a, 'b, T: Ord + Clone> Sub<&'b BTreeSet<T>> for &'a BTreeSet<T> {
466 type Output = BTreeSet<T>;
468 /// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`.
473 /// use std::collections::BTreeSet;
475 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
476 /// let b: BTreeSet<int> = vec![3, 4, 5].into_iter().collect();
478 /// let result: BTreeSet<int> = &a - &b;
479 /// let result_vec: Vec<int> = result.into_iter().collect();
480 /// assert_eq!(result_vec, vec![1, 2]);
482 fn sub(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
483 self.difference(rhs).cloned().collect()
488 impl<'a, 'b, T: Ord + Clone> BitXor<&'b BTreeSet<T>> for &'a BTreeSet<T> {
489 type Output = BTreeSet<T>;
491 /// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`.
496 /// use std::collections::BTreeSet;
498 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
499 /// let b: BTreeSet<int> = vec![2, 3, 4].into_iter().collect();
501 /// let result: BTreeSet<int> = &a ^ &b;
502 /// let result_vec: Vec<int> = result.into_iter().collect();
503 /// assert_eq!(result_vec, vec![1, 4]);
505 fn bitxor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
506 self.symmetric_difference(rhs).cloned().collect()
511 impl<'a, 'b, T: Ord + Clone> BitAnd<&'b BTreeSet<T>> for &'a BTreeSet<T> {
512 type Output = BTreeSet<T>;
514 /// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`.
519 /// use std::collections::BTreeSet;
521 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
522 /// let b: BTreeSet<int> = vec![2, 3, 4].into_iter().collect();
524 /// let result: BTreeSet<int> = &a & &b;
525 /// let result_vec: Vec<int> = result.into_iter().collect();
526 /// assert_eq!(result_vec, vec![2, 3]);
528 fn bitand(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
529 self.intersection(rhs).cloned().collect()
534 impl<'a, 'b, T: Ord + Clone> BitOr<&'b BTreeSet<T>> for &'a BTreeSet<T> {
535 type Output = BTreeSet<T>;
537 /// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`.
542 /// use std::collections::BTreeSet;
544 /// let a: BTreeSet<int> = vec![1, 2, 3].into_iter().collect();
545 /// let b: BTreeSet<int> = vec![3, 4, 5].into_iter().collect();
547 /// let result: BTreeSet<int> = &a | &b;
548 /// let result_vec: Vec<int> = result.into_iter().collect();
549 /// assert_eq!(result_vec, vec![1, 2, 3, 4, 5]);
551 fn bitor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> {
552 self.union(rhs).cloned().collect()
557 impl<T: Show> Show for BTreeSet<T> {
558 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
559 try!(write!(f, "{{"));
561 for (i, x) in self.iter().enumerate() {
562 if i != 0 { try!(write!(f, ", ")); }
563 try!(write!(f, "{}", *x));
571 impl<'a, T> Iterator for Iter<'a, T> {
574 fn next(&mut self) -> Option<&'a T> { self.iter.next() }
575 fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
578 impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
579 fn next_back(&mut self) -> Option<&'a T> { self.iter.next_back() }
582 impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
586 impl<T> Iterator for IntoIter<T> {
589 fn next(&mut self) -> Option<T> { self.iter.next() }
590 fn size_hint(&self) -> (uint, Option<uint>) { self.iter.size_hint() }
593 impl<T> DoubleEndedIterator for IntoIter<T> {
594 fn next_back(&mut self) -> Option<T> { self.iter.next_back() }
597 impl<T> ExactSizeIterator for IntoIter<T> {}
599 /// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
600 fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>,
601 short: Ordering, long: Ordering) -> Ordering {
603 (None , _ ) => short,
605 (Some(x1), Some(y1)) => x1.cmp(y1),
610 impl<'a, T: Ord> Iterator for Difference<'a, T> {
613 fn next(&mut self) -> Option<&'a T> {
615 match cmp_opt(self.a.peek(), self.b.peek(), Less, Less) {
616 Less => return self.a.next(),
617 Equal => { self.a.next(); self.b.next(); }
618 Greater => { self.b.next(); }
625 impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
628 fn next(&mut self) -> Option<&'a T> {
630 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
631 Less => return self.a.next(),
632 Equal => { self.a.next(); self.b.next(); }
633 Greater => return self.b.next(),
640 impl<'a, T: Ord> Iterator for Intersection<'a, T> {
643 fn next(&mut self) -> Option<&'a T> {
645 let o_cmp = match (self.a.peek(), self.b.peek()) {
648 (Some(a1), Some(b1)) => Some(a1.cmp(b1)),
652 Some(Less) => { self.a.next(); }
653 Some(Equal) => { self.b.next(); return self.a.next() }
654 Some(Greater) => { self.b.next(); }
661 impl<'a, T: Ord> Iterator for Union<'a, T> {
664 fn next(&mut self) -> Option<&'a T> {
666 match cmp_opt(self.a.peek(), self.b.peek(), Greater, Less) {
667 Less => return self.a.next(),
668 Equal => { self.b.next(); return self.a.next() }
669 Greater => return self.b.next(),
685 let mut m = BTreeSet::new();
690 assert!(m.clone() == m);
695 let mut x = BTreeSet::new();
696 let mut y = BTreeSet::new();
706 assert!(hash::hash(&x) == hash::hash(&y));
709 struct Counter<'a, 'b> {
714 impl<'a, 'b, 'c> FnMut(&'c int) -> bool for Counter<'a, 'b> {
715 extern "rust-call" fn call_mut(&mut self, (&x,): (&'c int,)) -> bool {
716 assert_eq!(x, self.expected[*self.i]);
722 fn check<F>(a: &[int], b: &[int], expected: &[int], f: F) where
723 // FIXME Replace Counter with `Box<FnMut(_) -> _>`
724 F: FnOnce(&BTreeSet<int>, &BTreeSet<int>, Counter) -> bool,
726 let mut set_a = BTreeSet::new();
727 let mut set_b = BTreeSet::new();
729 for x in a.iter() { assert!(set_a.insert(*x)) }
730 for y in b.iter() { assert!(set_b.insert(*y)) }
733 f(&set_a, &set_b, Counter { i: &mut i, expected: expected });
734 assert_eq!(i, expected.len());
738 fn test_intersection() {
739 fn check_intersection(a: &[int], b: &[int], expected: &[int]) {
740 check(a, b, expected, |x, y, f| x.intersection(y).all(f))
743 check_intersection(&[], &[], &[]);
744 check_intersection(&[1, 2, 3], &[], &[]);
745 check_intersection(&[], &[1, 2, 3], &[]);
746 check_intersection(&[2], &[1, 2, 3], &[2]);
747 check_intersection(&[1, 2, 3], &[2], &[2]);
748 check_intersection(&[11, 1, 3, 77, 103, 5, -5],
749 &[2, 11, 77, -9, -42, 5, 3],
754 fn test_difference() {
755 fn check_difference(a: &[int], b: &[int], expected: &[int]) {
756 check(a, b, expected, |x, y, f| x.difference(y).all(f))
759 check_difference(&[], &[], &[]);
760 check_difference(&[1, 12], &[], &[1, 12]);
761 check_difference(&[], &[1, 2, 3, 9], &[]);
762 check_difference(&[1, 3, 5, 9, 11],
765 check_difference(&[-5, 11, 22, 33, 40, 42],
766 &[-12, -5, 14, 23, 34, 38, 39, 50],
767 &[11, 22, 33, 40, 42]);
771 fn test_symmetric_difference() {
772 fn check_symmetric_difference(a: &[int], b: &[int],
774 check(a, b, expected, |x, y, f| x.symmetric_difference(y).all(f))
777 check_symmetric_difference(&[], &[], &[]);
778 check_symmetric_difference(&[1, 2, 3], &[2], &[1, 3]);
779 check_symmetric_difference(&[2], &[1, 2, 3], &[1, 3]);
780 check_symmetric_difference(&[1, 3, 5, 9, 11],
782 &[-2, 1, 5, 11, 14, 22]);
787 fn check_union(a: &[int], b: &[int],
789 check(a, b, expected, |x, y, f| x.union(y).all(f))
792 check_union(&[], &[], &[]);
793 check_union(&[1, 2, 3], &[2], &[1, 2, 3]);
794 check_union(&[2], &[1, 2, 3], &[1, 2, 3]);
795 check_union(&[1, 3, 5, 9, 11, 16, 19, 24],
796 &[-2, 1, 5, 9, 13, 19],
797 &[-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]);
802 let mut x = BTreeSet::new();
807 let mut y = BTreeSet::new();
813 let mut z = x.iter().zip(y.iter());
815 // FIXME: #5801: this needs a type hint to compile...
816 let result: Option<(&uint, & &'static str)> = z.next();
817 assert_eq!(result.unwrap(), (&5u, &("bar")));
819 let result: Option<(&uint, & &'static str)> = z.next();
820 assert_eq!(result.unwrap(), (&11u, &("foo")));
822 let result: Option<(&uint, & &'static str)> = z.next();
823 assert!(result.is_none());
827 fn test_from_iter() {
828 let xs = [1i, 2, 3, 4, 5, 6, 7, 8, 9];
830 let set: BTreeSet<int> = xs.iter().map(|&x| x).collect();
833 assert!(set.contains(x));
839 let mut set: BTreeSet<int> = BTreeSet::new();
840 let empty: BTreeSet<int> = BTreeSet::new();
845 let set_str = format!("{}", set);
847 assert!(set_str == "{1, 2}");
848 assert_eq!(format!("{}", empty), "{}");